Tutorial by Tom Liam Lynch.
Voyant Tools is an online service for text analysis. It can generate wordclouds (Cirrus) and other graphical overviews (Trend graphs, TermsBerries, ScatterPlots WordTrees, etc.) from uploaded texts and/or URLs. Texts may also be pasted directly, as in the example shown in the tutorial video. (The direct URL for the entire version of "Moby Dick" would also serve).
Using the interface it is advisable to notice the small function icons that appear (only) at mouse-over on the upper right questions marks. Most notably, the various graphical representations may be chosen here, and the large help section can be accessed by clicking the question mark and then following the link to "More help".
The help section contains detailed information that may help one configure the grapical tools, e.g. by selecting or deselecting words as stop words, by creating groups of words (e.g. positive vs. negative), by selecting colour schemes or directional settings for word groups, etc.
The creators of Voyant Tools request that you cite their work if using their service, quote:
"We appreciate you citing Voyant Tools, it helps to demonstrate the value of the tool and our recognizes our efforts. Depending on the citation style you need, you could adapt the following:
Sinclair, Stéfan and Geoffrey Rockwell, 2016. Voyant Tools. Web. http://voyant-tools.org/."